Adjustable table



ADJUSTABLE TABLE Filed Oct. 20, 1935 INVENTOR WM 70N 62 u/vpQa/srPatented May 26, 1936 UiTi-:D STATES PATENT OFFICE 7 Claims.

This invention relates to a table and more particularly to a table foruse in drafting and similar work. l

As is well known to those accustomed to making drawings, it is desirableto be able to shift frequently the angular position of the top of thedrafting table supporting the sheet upon which a drawing is being made,about a horizontal axis. This enables the draftsman to change hisposition with each change in the position of the top of the table sothat he does not tire as quickly as when working in one position.Changes in the angular position of the table top also enable the variousparts of the sheet to be more conveniently reached by the draftsman.

It is also desirable that the top of the table should be readilyadjustable vertically to suit the requirements of different draftsmen.Draftsmen of different statures ordinarily employr tables of differentheights and draftsmen of substantially the same statures may requiretables of different heights for efficient work.

The principal objects of the present invention are to improve theconstruction and mode of operation of tables for drafting and similarwork and to produce a table of this class in which the top of the tablemay be quickly and easily adjusted about a horizontal axis and will besecurely locked in position after each adjustment.

Another object of the invention is to produce a table ofthe classreferred to in which the top of the table may be readily adjustedvertically and may be firmly secured in position after each adjustment.Y

With the above and other objects in view the invention consists in atable embodying the novel and improved features hereinafter describedand particularly pointed out in the claims, the advantages of which willbe readily understood and appreciated by those skilled in the art.

The invention will be clearly understood from the accompanying drawingillustrating a drafting table construction embodying the invention inits preferred form and the following detailed description of theconstruction therein shown.

In the drawing,

Figure 1 is a perspective view illustrating a table embodying theinvention;

Figure 2 is a detail sectional view taken substantially on the line 2--2of Figure 1;

Figure 3 is a view in side elevation illustrating a modified form of theclamping or gripping brake mechanism for holding the top of the table inadjusted position; and

Figure 4 is a sectional view taken substantially on line 4-4 of Figure3.

In the construction illustrated in the drawing the table comprises a topor board indicated at 2 having reenforcing bars or cleats 3 secured tothe 5 under side thereof. The top is pivoted to swing about a horizontalaxis by means of bolts 4 passing through the cleats 3 and through theupper ends of the frame members or legs 6 engaging in slots in saidcleats. The frame members 6 extend 10 obliquely upwardly from the baseof the table and the lower ends thereof are pivoted by means of bolts 8to the horizontally extending frame members I0 at the base of the table.The frame members 6 are supported vertically by means of 15 the framemembers or legs I2 pivotally connected at their upper ends by means ofbolts I4 with the frame vmembers 6. The frame members I2 are eachcomposed .of outer and inner plates indicated respectively at I2a andI2b. Each of the plates 20 |219` is arranged to extend into a slot I6 inone of the base frame members Ii! and the correspondingV frame member I2is adjustably connected with the frame member I0 by means of a bolt I8arranged to be inserted in any one of a series of 25 openings 20 in theframe member Iii and passing through a corresponding opening in thelower end of the plate I2b. The lower ends of the plates I2a and |21)are secured together by means of bolts 25. Each of the plates I2a isarranged 30 to terminate with its semi-circular lower end just above thecorresponding frame member IIJ.

The frame members I2, as illustrated in the drawing, are connected bycross frame members 22 and 24 to which may be added suitable diagonal 35cross members to assure such necessary transverse stability as may berequired. The ends of these cross frame members are secured to theplates I2a by means of screws or other suitable fastening devices butare not directly attached to the 40 plates I2?) in the presentembodiment of the invention.

The height of the table top` 2 may be adjusted vertically by removingthe bolts I8 and by swinging the frame members l2 forwardly or rear- 45wardly about the pivot bolts I4 according to whether it is desired tolower or raise the top, said frame members being nally adjusted tolocate the opening in each of the plates IZb in registration with one ofthe openings 20 in the corresponding base frame member I (I. The tabletop is then secured in its adjusted vertical position by passing thebolts I8 through the proper openings 20 in the base fram'e members I0and 55 through the registering openings in the lower ends of the plates|2b.

The pivoting of the table top 2 on the pivot bolts 4 enables the tableto be swung about a hori- Zontal axis into any desired position. Themechanism for holding the table top in adjusted position comprises links26 pivotally connected at their upper ends by means of bolts 28 to thecleats 3. At their lower ends the links 26 are pivotally connected bybolts 32 respectively to brake shoes 34 arranged to engage the underside of frame members 6. Each of the brake shoes 34 is connected bylinks 36 arranged upon opposite sides or" the corresponding framemembers 6 with a brake shoe 35 arranged to engage the upper side of thecorresponding frame member 6, the brake shoes 34 and 55 thus beingarranged in pairs connected by said links. The brake shoe 35 of eachpair is pivoted to the corresponding set of links 36 by means of a bolt5l. The links 36 connecting the brake shoes of each pair are of such alength that when these links are in positions substantiallyperpendicular to the corresponding frame member 6, the distance betweenthe braking faces of the brake shoes will be greater than the width ofthe frame member 6. The brake shoes of each pair are acted upon by aspring 46 which tends to move the brake shoe 35 downwardly along thecorresponding frame member 6 with relation to the brake shoe 34.

The links 36 and brake shoes 35 and 35 are so constructed and arrangedthat the angle between the line of tension of the links (the lineconnecting the respective axes of the bolts 32 and 3l) and a lineperpendicular to the inner faces of the brake shoes is always less thanthe friction angle. The friction angle, of course, will vary with thematerials used in the brake shoes and in the frame members 6 which theyengage.

With the above construction, any attempt to tilt the table top 2 in adirection to raise the upper portion of the top, Figure l, will causethe brake shoes to grip the frame members 6 frictionally to such adegree as to prevent the tilting of the top. The greater the forceapplied to the table top tending to tilt the same, the heavier will bethe gripping action of the brake shoes on the member 6. The table topmay, however, be readily tilted in a direction to lower the upperportion of the top. In this case, through the links 26, the brake shoes34 will be first moved downwardly, thereby freeing the brake shoes fromgripping engagement with the members 6 and the entire brake mechanism`will then slide freely downwardly along said members.

In order to enable the operator readily to free the brake mechanism fromgripping engagement with the member 6 so that the table top may betilted in a direction to raise the upper portion of the top, cords 42are each connected at one end to one of the brake shoes 35. The otherend of each of these cords is connected with a cord i4 which is passedover a pulley 45 secured to the under side of the table top adjacent theupper portion thereof and this cord also is passed through a guide eye48 secured to the under side of the table top adjacent the lower portionthereof. By pulling upon the cord l2 the brake shoes 35 may be movedupwardly along the frame members 6 against the action of the springs 40,thereby freeing the brake shoes from gripping engagment with the members6 and allowing said shoes to be moved upwardly along said members.

In the construction shown in Figure 3 the brake mechanism for holdingthe top of the table in adjusted position is arranged to hold the saidtop positively from pivotal or tilting movement in either direction. Thesaid mechanism comprises a brake shoe 56 arranged to engage the lowerside of the fram'e member or leg 6 to which shoe are pivotally connectedthe lower ends of one pair of links 26. The said mechanism alsocomprises two lbrake shoes 52 each arranged to engage the upper side ofthe frame member 6 in opposed relation to the shoe 50. Each of the shoes52 is connected with the brake shoe 55 by means of links 54 embracingthe leg 6. Secured to the brake shoe 56 on each side thereof is a stopplate 56 located between the links 54 on the corresponding side of saidshoe. The lengths of the links 54 and the construction and arrangementof the brake shoes 52 and the stop plate 56 are such that when the linksare engaged with said plates the shoes 52 will be out of grippingengagement with the frame member 6 as shown in Figure 3, the adjacentfaces of said brake shoes then being in contact as shown in said figure.

The brake shoes 52 are forced yieldingly apart to bring the said shoesinto contact with the adjacent face of the frame member 6 by means of acoiled spring 58 interposed between the shoes. The links 5K4 on eachside of the frame member 6 are drawn into engagement with the respectivestop plates 56 by means of cords 66 each attached at one end to one ofthe links 54. The other end of each of these cords is connected to acord 62 which passes through a guide eye 64 secured in one of the stopplates 55.

With the above construction when the cord 62 is released the spring 58forces the brake shoes 52 into contact with the upper side of the framemember 6. Any force applied to the brake shoe 5D tending to move saidshoe upwardly will cause said shoe and the lower brake shoe 52 to gripthe frame member 6. Also, any force applied to the shoe 56 tending tomove the said shoe downwardly would cause said shoe and the upper shoe52 to grip said frame member. Thus the brake mechanism will securelyhold the top of the table from tilting movement in either direction.

There is, of course, a set of brake shoes 56 and 52 arranged to engageeach of the frame members S. The cords 62 are connected to a commonactuating cord such as the cord 44 shown in Figure I which is operatedmanually by the operator.

When the operator desires to tilt the top of the table, he pulls thecords 62 in the direction of the arrow, Figure 3. The links 54 on eachside of the frame member 6 are thus moved toward each other intoengagement with the corresponding stop plate 62 and the brake shoes 52are thus released from gripping engagement with said frame member. Withthe parts in this position the brake shoes 56 and 52 may be readilymoved longitudinally of the frame member 6 by a force tending to slidethe brake shoe 56 longitudinally of said frame member. Thus the tabletop may then be tilted freely in either direction.

In another modied form of the invention the brake shoes 34 are rigidlyconnected by suitable cross bars as are also the brake shoes 38 and thelinks 26 and 36 are replaced by tension cords. The construction shown inthe drawing, however, is preferred, since the brake mechanism maintainsits adjustment in a more reliable manner and there is very littlestretch in the ten- 75 sion members and therefore greater certainty inthe operation of the table.

'I'he table construction disclosed in this application also has theadvantages that it may be readily disassembled and compactly arrangedfor transportation. In disassembling the table the brake mechanism forcontrolling the tilting of the top of the table is first disassembledand removed. The two pivot bolts t are then removed and the top of thetable is detached from the upper ends of the frame members 6. The boltsI 4 are then removed, thereby freeing the frame members E which maybefolded down alongside the base frame members l 0. The bolts 25 are nextremoved, thereby freeing the plates IZa from the plates l2b and theplates |2, together with thel attached cross-frame members 22 and 24 maybe lifted away, leaving the plates |217 free. These plates maythereafter be folded down into the slots i6 in the base frame members.This completes the disassembling of the table.

Tables embodying the present invention not only may be employed indrafting Work but also may be used with advantage in sketching,painting, writing and in many other operations.

It is to be understood that the invention is not limited to theparticular construction and arrangement of parts of the illustratedembodiment of the invention but that this embodiment is merelyillustrative of the invention and that the invention may be embodied inother forms Within the scope of the claims.

Having explained the nature and object of the invention and havingspecifically described a construction embodying the invention in itspreferred form, what is claimed is:-

1. A table comprising supporting legs, a top pivotally attached to saidlegs and means for securing the top in adjusted position, said meanscomprising friction brake elements Which are slidable along the legs,means for normally frictionally locking said brake elements to the legs,links attached to the top and to the friction brake elements, andmanually operable means for releasing said brake elements.

2. A table comprising supporting legs, a top pivotally mounted on saidlegs and means for securing the top in various adjusted positions, saidmeans comprising a pair of friction brake elements on opposite sides ofeach leg, one of said pair comprising a leading brake element and theother a trailing brake element, links con-- necting each pair of brakeelements on opposite sides of each leg in such a manner that thetrailing brake element on each leg is frictionally restrained fromsliding along the leg by reason of the less than friction angle at whichthe displacing force is applied to this trailing element through itslink connecting it to the leading brake element, links pivotallyattached to the table top and connected to the friction brake elements,and manual means for releasing the brake elements for sliding movementalong the legs.

3. A table comprising legs, a top pivotally supported on said legs,friction brake elements slidable along the legs, links attached to saidtop and to said brake elements, means normally acting to render saidbrake elements operable consisting of linkage between pairs of brakeelements Whereby any force tending to move one of the brakeelementsalong the legs is transmitted to another of the brake elementsthrough less than the friction angle, thus making said brake elementeffective to resist motion and thereby holding the topi in position, andmanually operable means for releasing said brake elements for slidingmovement along the legs.

4. A table comprising supporting legs, a top pivotally attached to thelegs, links pivoted to the top and said brake elements and arranged todefine the angular adjustment thereof, friction brake elements mountedon each link and slidable along the legs and frictionally engaging thelegs, links joining the brake elements in pairs With a link between eachpair and so arranged that any displacing force applied to one of thebrake elements of a pair is transmitted to the other brake element ofsaid pair at less than the friction angle, and quick acting means torelease the brake elements to enable. the top to be adjusted.

5. A table having a top, a structure for supporting said top for tiltingmovement in a generally vertical direction, means normally effective tohold the top positively from tilting movement in either direction, whenadjusted to various positions, said means consisting of friction brakeelements joined to the top by links and slidable along the supportingstructure, links joining pairs of brake elements in such manner that anydisplacing force applied to one of the brake elements is transmitted toanother of the brake elements at less than the friction angle thusrendering it immobile, and manually operable means for releasing saidbrake elements to permit movement of said top in either direction.

6. A table having a top, legs for pivotally supporting said top fortilting movement in a generally vertical direction, brake means whichare slidable along the legs, links pivotally attached to said top andjoined to said brake means, said brake means being normally effective tohold said topl in any position within their range of movement, andmechanism for effecting quick release of said brake means.

7. A table comprising legs, a top pivotally attached to the legs, linkspivoted to the top and arranged to dene the angular adjustment thereof,friction brake. elements mounted on the links and slidable along thelegs, links joining the brake elements in pairs whereby any displacingforce applied to one of the brake lelements of each pair is transmittedto the other brake element of said pair at less than the friction anglethereby causing the brake elements to frictionally engage the legsthereby locking the top in adjusted position.

WILTON G. LUNDQUIST.

